JPH0421746Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a brake system for vehicles equipped with a diesel engine, and in particular, to maintain the boosting effect after an abnormality occurs in the vacuum circuit that guides the vacuum booster to the brake vacuum booster. Regarding the technology that makes it possible.

<Prior art> A brake booster is installed in a vehicle in order to reduce driver fatigue, increase braking ability, and shorten braking distance. For example, a vacuum booster (master back) that utilizes negative pressure (vacuum) generated during the intake stroke of an engine is known.

In this case, in vehicles equipped with diesel engines, the level of negative pressure in the intake pipe is generally lower than in gasoline vehicles, so an engine-driven vacuum pump is installed to generate vacuum, and the generated vacuum is removed. A system for storing vacuum tanks is adopted.

In such a braking system for a vehicle equipped with a diesel engine, if an abnormality occurs in the vacuum circuit that leads the vacuum booster to the vacuum booster, such as when the vacuum pump is damaged, vacuum cannot be stored in the vacuum tank, and the vacuum booster fails. There are inconveniences such as the fact that the vacuum cannot be guided to the force device, and the boosting effect eventually disappears, impeding the braking ability.

For this reason, for example, if the vacuum pump is damaged and no longer performs its function,
Some vehicles are equipped with systems that warn of this.

This system is shown in FIG. 2. A vacuum pump 2 driven by an engine 1 and a vacuum tank 3 are connected by a vacuum passage 5 with a check valve 4 interposed therebetween.

A vacuum switch 6 is installed in the vacuum passage 5, which senses the negative pressure in the passage 5 and is turned on and off according to the negative pressure.

The vacuum switch 6 is connected in series to a power source 8 together with a warning lamp 7, and is turned ON to light up the warning lamp 7 when the vacuum pump 2 is damaged and no longer performs its function. It's becoming like that.

<Problems to be solved by the invention> However, in such a conventional system, only a warning is issued by the warning lamp 7, and the vacuum in the vacuum tank 3 is reduced by using the brake two or three times. Because the pressure is consumed, the vacuum cannot be guided to the vacuum booster, and the boosting effect eventually disappears, so it is not possible to maintain the boosting effect after an abnormality occurs, and this is a problem. The dot was hot.

Incidentally, the applicant of the present application has previously proposed a technique in which the exhaust brake shutter and the main brake are operated by a vacuum chamber in Japanese Utility Model Application Publication No. 55-161032.

The present invention was developed in view of the conventional problems as described above, and makes it possible to maintain the boosting effect after an abnormality occurs, such as when the vacuum pump is damaged and no longer performs its function. The purpose of this invention is to solve the above-mentioned conventional problems.

<Means for Solving the Problems> Therefore, the present invention provides a brake system for vehicles equipped with a diesel engine, which includes an abnormality detection means for detecting an abnormality in the vacuum circuit, and an abnormality detection signal emitted from the means to detect an abnormality in the engine. a vacuum valve for connecting a downstream side of the throttle valve in the intake passage and the vacuum tank; The structure has a passageway.

<Function> When an abnormality in the vacuum circuit is detected, the throttle valve is operated to a predetermined opening degree in the closing direction, thereby causing negative pressure in the intake passage to act on the vacuum passage, creating a negative pressure inside the vacuum tank. The pressure is maintained, making it possible to maintain the boosting effect after an abnormality occurs.

<Example> Hereinafter, an example of the present invention will be described based on FIG. 1.

In the figure, a vacuum pump 9 and a vacuum tank 10 driven by an engine 8 are connected to a vacuum passage 1 with a check valve 11 interposed therebetween.
It is connected by 2.

A vacuum switch 13 is installed in the vicinity of the connecting portion of the vacuum passage 12 with the vacuum pump 9, which senses the negative pressure in the passage 12 and is turned on and off in accordance with the negative pressure.

The vacuum switch 13 has a main body 13a.
A diaphragm 14 is provided in the inner space to partition the space into two chambers A and B, and a passage 1 communicates between one chamber A and the vacuum passage 12.
5 is provided. A switch piece 16 is attached to the diaphragm 14, which opens contacts a and b provided in chamber B when negative pressure acts in chamber A, and closes contacts a and b when no negative pressure acts. There is. These contacts a and b are connected to a power source 1 along with an electromagnetic coil and a warning lamp 17 of an electromagnetic on-off valve to be described later.
8 in series.

A vacuum passage 19 for driving a throttle valve, which will be described later, is connected between the vacuum tank 10 and the check valve 11 of the vacuum passage 12. A power chamber 20 is connected to the end of the vacuum passage 19.
An electromagnetic on-off valve 21 is interposed in the middle.

The power chamber 20 includes a diaphragm 21 disposed in the interior space of its main body 20a so as to partition the space into two chambers C and D, and a vacuum passage 19 communicates with the chamber D. diaphragm 21
A rod 22 protruding outward from the chamber of the chamber 20 is fixedly attached to the engine, and the rod 22 expands and contracts as the diaphragm 21 deforms to open the throttle valve provided in the intake passage 23 of the engine 8. 24. In this case, the power chamber 20
When the diaphragm 21 deforms against the spring force of the spring 25 by acting on the chamber D through the rod 22, the rod 22 operates the throttle valve 24 to a predetermined opening degree in the closing direction.

The electromagnetic on-off valve 21 has an electromagnetic coil 21a.
When energized, the valve body 21b is attracted and opened.

The downstream side of the throttle valve 24 in the intake passage 23 and the master bag 10 are connected via an emergency back passage 27 having a check valve 26 interposed therebetween.

Here, the vacuum switch 13 constitutes an abnormality detection means according to the present invention that detects an abnormality in the brake vacuum circuit, and the vacuum passage 19, the power chamber 20, and the on-off valve 21 constitute an abnormality detection means for detecting an abnormality in the brake vacuum circuit. The throttle valve driving means according to the present invention is configured to operate the throttle valve to a predetermined opening degree in the closing direction based on the abnormality detection signal generated by the throttle valve.

Next, the operation of this configuration will be explained.

If an abnormality occurs in the vacuum circuit, such as damage to the vacuum pump 9, negative pressure will no longer act on chamber A of the vacuum switch 13, contacts a and b will be closed by the switch piece 16, and the warning lamp 17 will light up. At the same time, the electromagnetic coil 21a of the electromagnetic on-off valve 21 is excited, and the valve body 21b is opened. As a result, the Baquium passage 19 is opened,
Negative pressure in the vacuum tank 10 acts on the chamber D of the power chamber 20 through the vacuum passage 19, the diaphragm 21 deforms against the spring force of the spring 25, and the rod 22 moves the throttle valve 24 in the closing direction. Operate to achieve a predetermined opening degree.

In this way, when the throttle valve 24 is operated to a predetermined opening degree in the closing direction, the negative pressure in the intake passage 23 acts on the vacuum passage 12, and the vacuum tank 10
Negative pressure is maintained within.

The opening of the throttle valve 24 is such that when it is closed, the negative pressure in the intake passage 23 becomes a negative pressure sufficient to perform a boosting action, and the throttle valve 24 is opened at such an opening that the negative pressure in the intake passage 23 becomes a negative pressure sufficient to perform a boosting action. Be sure to operate at an opening that will not cause this.

According to the above configuration, after an abnormality occurs, such as when the vacuum pump 9 is damaged and no longer performs its function, the boosting effect can be maintained by using the negative pressure generated in the intake passage 23. This allows for more effective response to emergencies, rather than just issuing a warning using a warning lamp, as in conventional systems.

In the above embodiment, the vacuum passage 19, the power chamber 20, and the on-off valve 21 constitute the throttle valve driving means, and the throttle valve 24 is operated by the negative pressure inside the vacuum tank 10. Throttle valve 2 by electrical means
4 may be operated.

<Effects of the invention> As explained above, according to the invention, the negative pressure generated in the intake passage of the engine can be reduced after an abnormality occurs such as when the vacuum pump is damaged and no longer performs its function. This has a great practical effect in that it can be utilized to maintain the boosting effect, making it possible to more effectively respond to emergencies.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, and FIG. 2 is a schematic diagram of a conventional example. 8... Engine, 9... Vacuum pump, 10...
...Bakiyum tank, 12...Bakiyum passage,
13... Vacuum switch, 19... Vacuum passage for driving the throttle valve, 20... Power chamber, 21... Electromagnetic on-off valve, 23... Intake passage, 24... Throttle valve, 27... Emergency vacuum passage.

Claims (1)

[Scope of utility model registration request] It is equipped with a vacuum booster for brakes and includes a vacuum pump driven by an engine, and a vacuum tank that stores vacuum generated by the vacuum pump, and the vacuum booster A brake system for a diesel engine vehicle equipped with a vacuum circuit that guides vacuum stored in a tank includes an abnormality detection means for detecting an abnormality in the vacuum circuit, and an abnormality detection signal emitted from the means to detect an abnormality in the intake air of the engine. A throttle valve driving means for operating a throttle valve provided in the passage to a predetermined opening degree in a closing direction, and a vacuum passage connecting the downstream side of the throttle valve of the intake passage and the vacuum tank. A braking device for a vehicle equipped with a diesel engine.